1. Field of the Invention
The present invention relates to a disk reproducing apparatus and a disk reproducing method.
2. Prior Art
A function called shock proofing is known which is provided in apparatuses for reproducing music, image data or the like recorded on recording media, hard disc for example (hereinafter referred to as “disk reproducing apparatus”). This shock proofing function is a function of preventing data from skipping because of shock or the like as explained below.
The idea is to have data pre-read from a recording medium to a memory in a disk reproducing apparatus at a higher speed than the ordinary reproducing speed beforehand. And later, the data is read out from the memory and reproduced. That could keep data from skipping even if a shock occurs while data stored on the memory is reproduced. In other words, that could bring back the pickup to an original position to read data again if a shock occurs.
A disk reproducing apparatus provided with a shock proofing function has also a feature of reproducing data precisely. That is, in case a reading error like data error occurs, reading this error block will be retried. But it is usual that this retrial will be made only when pre-read data is stored on the memory.
Meanwhile, the Real-Time Recording/Playback(RTR) standards (Mt. Fuji Commands for Multimedia Device SFF8090i v4) attract attention as standards on the recording of such data as music and images on such recording media as DVD-RAM and DVD-R. Such data as music and images are to be continuously recorded. It is more important that data of the RTR type should continue to be reproduced uninterruptedly rather than being reproduced precisely. For this reason, in case a block where recording is made is a defective block, data of the RTR type is treated in a way different from that for ordinary data as explained below.
That is, for ordinary data to be recorded on a defective block, SLR flag “0,” defective block address α and alternative block address β are registered linked to each other in advance as shown in FIG. 3(b) {circle around (1)}. For data of the RTR type to be recorded on a defective block, meanwhile, SLR flag “1,” defective block address A and NULL data are registered linked to each other in advance as shown in FIG. 3(b) {circle around (2)}.
The alternative block is a reserve block to replace the defective block where data is recorded. The SLR (status of linear replacement) flag is a flag to indicate whether the defective block is replaced; “0” shows that the defective block is replaced while “1” indicates that no replacement is made.
In other words, ordinary data is recorded on the alternative block while data of the RTR type is recorded on the defective block. Naturally, there is no need to ensure that data of the RTR type is written on a defective block correctly.
Under that arrangement, ordinary data is reproduced this way. When data is reproduced up to address α−1, address β is sought, and the alternative block at this address β is reproduced, the pickup returns to address α+1 and reproduces data from that point. In reproducing the RTR type, meanwhile, if data is reproduced up to address A−1, data after address A will be reproduced sequentially.
That is, for data of the RTR type, it is more important that data continue to be reproduced uninterruptedly rather than precisely, and once address A is read as mentioned above, this data may be forwarded to the reproduction requester (host computer, for example) even if a reading error like data error occurs.
In a disk reproducing apparatus provided with a shock proofing function, the system is so designed that if a reading error like data error occurs, reading this error block will be retried so that data is read precisely as mentioned above. In other words, according to the prior art, when address A is read and a reading error like data error occurs, reading this error block will be retried.
However, the address A is an address of a defective block with data of the RTR type recorded thereon (hereinafter referred to as “RTR defective block”), and if reading is retried like that, it is almost certain that data can not be read correctly.
Namely, in reproducing recording media such as CD and DVD-ROM in which defective blocks are not controlled with a defective block list, it is not known whether a block with a reading error can be read or not, and it is useful to retry reading this error block.
On the other hand, to retry reading an RTR defective block is to retry reading data recorded on the defective block, and it can hardly be said that it is useful. Furthermore, to retry reading like that could affect real time reproduction and make it impossible to reproduce data of the RTR type uninterruptedly.